340 
The easternmost beds have been invaded by igneous 
intrusions which are comparatively absent from the western 
side of the axis. (27) 
These sedimentary beds contain an interstratified glacial 
tilite. They have been designa as Lower Cambrian by 
Prof Howchin, but the possibility of their being 
Proterozoic must not be denied. ; 
Age of the Intrusion.—The granitic mass of Ca Wil- 
loughby is intrusive into the eastern representatives of this 
series. Howchin has shown that the late Palaeozoic (Permo- 
Carboniferous) glacial deposits overlie the old metamorphic 
ocks of eastern Kangaroo Island, and are represented near 
i On further analysis, however, it would appear that these 
limits can be somewhat narrowed. It is clear that in Permo- 
Carboniferous times the granite was exposed at the surface. 
The v 
Cambrian time, for the Proterozoic age of these beds 1s 
dependent on a disconformity between their western repre- 
sentatives and the Cambrian Archaeocyathinae, limestones. 
. The absence of Ordovician beds at the edges of the Cam- 
brian geosyncline points to the folding of this geosyncline at 
., the close of the Cambrian or in Ordovician time. 
turbed this area to the present day. vid : 
inclusions of country rock in the granite indicates that partial 
Med lu I M 
This view of the structure of the Mount Lofty Ranges 
miden 
o , particularl G. Woolnough. 
anticlinorial character of the 
Valley, e an easterly 
£ with the great angular unconformity of 
to Victor H ore com- 
. town-Mount msg ‘Barossa. The possible Proterozoic 
age of the westernmost beds affects € esa c umm not at all  ' 
t 
